Question

Which organism would make the best index fossil? Why?

Answer 1

Answer:

A good index fossil is one with four characteristics: it is distinctive, widespread, abundant, and limited in geologic time. Because most fossil-bearing rocks formed in the ocean, the major index fossils are marine organisms.

Answer 2

Answer:

Marine organisms are the best index fossil because most of the fossil-bearing rocks are recovered from the oceans.

Explanation:

Index-fossil: The organisms which existed during the periods of geologic time and thus are used as guidelines to interpret the age of the rocks in which they are well preserved.

The best index fossil should have the four basic characteristics namely widespread, distinctive, abundant and limited to geologic time.

• Few fossils are considered index fossils.

• They help geologists match rock layers. To be considered an index fossil it must be widely distributed. It must be an organism that existed for a brief period of time.

• Index fossils are useful to reveal the age of the rock layers.    

• The dinosaur fossils are found mainly in sedimentary rocks. These rocks are flat layers called strata.  

• Haramiyids are the youngest index fossil. Titanosaur is the biggest fossil ever found.

Hence, the best index fossils are marine organisms.